In networks and the like, control planes provide automatic allocation of network resources in an end-to-end manner. Exemplary control planes may include Automatically Switched Optical Network (ASON) as defined in G.8080/Y.1304, Architecture for the automatically switched optical network (ASON) (02/2005), the contents of which are herein incorporated by reference; Generalized Multi-Protocol Label Switching (GMPLS) Architecture as defined in Request for Comments (RFC): 3945 (10/2004) and the like, the contents of which are herein incorporated by reference; Optical Signaling and Routing Protocol (OSRP) from Ciena Corporation which is an optical signaling and routing protocol similar to PNNI (Private Network-to-Network Interface) and MPLS; or any other type control plane for controlling network elements at one or more layers, and establishing connections there between. As described herein, these control planes may be referred to as control planes as they deal with routing signals at Layers 1 and 2, i.e., time division multiplexing (TDM) signals such as, for example, Synchronous Optical Network (SONET), Synchronous Digital Hierarchy (SDH), Optical Transport Network (OTN), Ethernet, MPLS, and the like. Control planes are configured to establish end-to-end signaled such as sub-network connections (SNCs) in ASON or OSRP and label switched paths (LSPs) in GMPLS and MPLS. All control planes use the available paths to route the services and program the underlying hardware.
Control planes generally support two type of automated provisioning mechanisms for determining a route for connection establishment: 1) route information is explicitly specified by an operator; or 2) an optimal route computation is automatically performed by control plane, using a constraint-based routing algorithm. Conventionally, constraint-based routing algorithms determine a path in a network based on several constraints such as available bandwidth, color (optical virtual private network number), delay, administrative weights, priority, fragmentation, etc. Specifically, conventional constraint-based routing algorithms only account for current attributes in decision making and do not account for parameters like future bandwidth demand for expanding a connection while making decision for route selection. This creates inefficient decisions over time by not accounting for future capability of links. For example, an issue can arise where some connection that needed an opportunity may not be able to find path, because some other connection has already taken its resources, when that other connection had alternative options available. Since that other connection made choices based current constraints, even when that connection could have chosen an alternate path, it may exhaust the future opportunity that a path was offering for other connections that needed it. There is a so-called lost opportunity here.
Specifically, conventional techniques have various shortcomings. In case some links have more capability with respect to type of connections/bandwidth they can support, and since conventional techniques do not use this as a constraint in route computation, one may end up exhausting all the links that support those capability for other type of connections. This may leave some connections starving for bandwidth, because links that were capable of those bandwidth types were consumed by connections that could had been allocated to lesser capable links. Since conventional techniques are based on current resource constraints and do not account for future opportunity that some connections (e.g., flex-based, Layer 2/3, etc.) may demand for dynamic growth of bandwidth. This may restrict hitless dynamic growth of connections, because the bandwidth was consumed by connections that could have been allocated to links not offering such opportunity.